Latest CTS Aptitude Question SOLUTION: A secret can be told only 2 persons in 5 minutes .the same person tells to 2 more persons and so on . How long will take to tell it to 768 persons ? a)47.5 min b)50 min c) 500 min

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(#M40020048) CTS Logical Reasoning question analytical Keep an EYE

A secret can be told only 2 persons in 5
minutes .the same person tells to 2 more persons
and so on . How long will take to tell it to 768
persons ?
a)47.5 min b)50 min c) 500 min d)49 min

Asked In CTS Nilesh singh (10 years ago)

Unsolved Read Solution (7)

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Read Solution (7) :

Priya Sharma  (10 years ago)

2^9=512 2^10=1024 for 512 persons time taken=>9*5=45 for telling next 512 persons tym taken =5 min. thus for next 256 persons time taken =(5*256)/512=2.5. total time taken is 45+2.5=47.5

Is this solution Helpfull? Yes (14) | No   

bhaskar jana  (10 years ago)

2^9=512 for this time will b taken=5*=45min.Then 1024-512=512.it will b minus from 768.i.e 768-512=254.for telling 254 pensons it will take=5*254/512=2.48 min.So total time=45+2.48=47.5(approx)

Is this solution Helpfull? Yes (8) | No (7)  

yojana  (10 years ago)

1 person to 2 persons,
2 to 4 => 2 to 2^2
4 to 8 => 2^2 to 2^3
8 to 16 => 2^3 to 2^4
2^4 to 2^5
2^5 to 2^6
2^6 to 2^7
2^7 to 2^8
2^8 to 2^9
512 to 1024 => 2^9 to 2^10
they asked for 768 members
i.e., 512/2 = 256
512+256 = 768
512 in 5*9 = 45 min
256 in 5/2 = 2.5 min
therefore 768 in 47.5 min

Is this solution Helpfull? Yes (8) | No (2)  

Ish Mishra  (10 years ago)

This is just a function that triples itself every 5 minutes. You start with one person, and every generation is x3 so you have 1, 3, 3^2, 3^3, 3^4,

3^n=768
n=9.16

Answer is 5x9.16=50(approx)min

Is this solution Helpfull? Yes (3) | No (9)  

seema chauhan  (10 years ago)

the series of saying secrate to people in 5 min is 2 4 8 16 32 64 128 256 512 1024
which is 2^10 ,and time taken betweem them is 5 min so total time =10*5=50 min

Is this solution Helpfull? Yes (3) | No (14)  

nayan  (10 years ago)

2^x = 768

x = log(768) / log(2)

x = 9.5849

Then times that by the doubling time = 5 minutes

9.5849 * 5 = 47.9245 minutes = 47 minutes, 55.47 seconds

Is this solution Helpfull? Yes (1) | No   

pragyanpradhan  (10 years ago)

exact ans is 47.92.procedure is same like above

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